*> 100 Cool Things - http://cobolrocks.codeplex.com/
*> Copyright (c) 2009
*> by Emerson Lopes (emersonlopes@gmail.com)
*>
*> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated 
*> documentation files (the "Software"), to deal in the Software without restriction, including without limitation 
*> the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and 
*> to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*>
*> The above copyright notice and this permission notice shall be included in all copies or substantial portions 
*> of the Software.
*>
*> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 
*> TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
*> THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
*> CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
*> DEALINGS IN THE SOFTWARE.


CLASS-ID. Singleton AS "CoolThings.Singleton".

    *> Static data and methods
    static.
        data division.
           working-storage section.
           01 instance usage object reference SINGLETON is private.
        
        procedure division.
            method-id. GetInstance AS "GetInstance".
                data division.
                    linkage section.
                    01 localSingleton usage object reference SINGLETON.
                    
                procedure division returning localSingleton.
                    if (instance equal null) then
                          invoke Singleton "NEW" returning localSingleton
                          set    instance  to localSingleton
                    else
                          set    localSingleton    to instance
                    end-if
                    
            end method GetInstance.
    end static.

    *> Instance's data and methods       
    object.
        environment division.
            data division.
                working-storage section.
                01   counter pic s9(04) value zeros.
        
        procedure division.
            method-id. NEW is private.
                data division.
                procedure division.
                    move zeros   to counter.
                
            end method NEW.
            
            method-id. GetCounter as "GetCounter".
                data division.
                    linkage section.
                    01 localCounter  pic s9(04).
                        
            procedure division returning localCounter.
               add   1       to counter.
               
               move  counter    to  localCounter.
                
            end method GetCounter.
            
    end object.        

END CLASS Singleton.



